Coupled-mode-induced transparency in aerostatically tuned microbubble whispering-gallery resonators.

Area of Science:

• Optics and Photonics
• Materials Science
• Acoustics

Background:

• Whispering-gallery mode resonators are sensitive to external stimuli.
• Microbubble resonators offer unique optical properties for sensing.
• Coupled-mode phenomena can be exploited for optical switching and sensing.

Purpose of the Study:

• To realize coupled-mode-induced transparency in a single microbubble resonator.
• To investigate the pressure-induced shifting rates of different radial order modes.
• To establish a foundation for microbubble sensing applications.

Main Methods:

• Utilized aerostatic tuning for precise pressure control.
• Employed finite element simulation to model strain and stress effects on modes.
• Conducted experimental verification of simulated pressure-induced shifts.
• Achieved transparency spectrum by tuning modes via pressure.

Main Results:

• Demonstrated coupled-mode-induced transparency in a single microbubble.
• Observed distinct pressure-induced shifting rates for different radial order modes (GHz/bar difference).
• Confirmed simulation predictions experimentally.
• Obtained and fitted transparency spectrum lineshapes with theoretical models.

Conclusions:

• Coupled-mode-induced transparency is achievable in microbubble resonators.
• Pressure tuning offers a method to control mode interactions.
• The distinct mode shifting rates are critical for precise tuning.
• This research provides a basis for developing novel microbubble-based sensors.